Ignition Coil and Iridium Spark Plugs for Cadillac XLR (2004-2009) 4.6L

Direct-Fit Ignition Coil and Iridium Spark Plug Service Kit for 2004-2009 Cadillac XLR

Restores Peak Combustion Efficiency: This comprehensive 8-cylinder ignition tune-up kit replaces deteriorating factory coil-on-plug packs and worn spark plugs to eliminate misfires, hard cold starts, and secondary ignition breakdown under load.

The Stock XLR Secondary Ignition Breakdown

The 4.6L Northstar DOHC V8 engine bay generates substantial thermal cycling, which degrades factory coil-on-plug epoxy potting and interior secondary copper windings over time. This thermal fatigue causes insulation breakdown, micro-arcing, and high-voltage leakage, manifesting as cylinder misfires (P0300-P0308), erratic idling, and reduced throttle response. Simultaneously, standard factory plugs suffer from electrode gap erosion, requiring higher secondary voltage that accelerates coil failure.

The Engineering Solution

This direct-replacement kit pairs eight high-dielectric coil-on-plug assemblies with eight fine-wire iridium spark plugs. The ignition coils feature premium internal copper windings and reinforced thermoplastic housings designed to withstand elevated underhood operating temperatures without dielectric puncture. Paired with high-melting-point iridium core electrodes, this kit ensures consistent arc delivery, reduced quench effect, and complete fuel atomization across the entire rev range.

Technical Specifications

Compatibility

• 2004 Cadillac XLR Base 4.6L V8 (Northstar LH2)
• 2005 Cadillac XLR Base 4.6L V8 (Northstar LH2)
• 2006 Cadillac XLR Base 4.6L V8 (Northstar LH2)
• 2007 Cadillac XLR Base 4.6L V8 (Northstar LH2)
• 2008 Cadillac XLR Base / Platinum 4.6L V8 (Northstar LH2)
• 2009 Cadillac XLR Platinum 4.6L V8 (Northstar LH2)

The Cadillac Precision Standard

Engineered to meet factory electrical tolerances, this ignition set preserves the seamless power delivery, refined low-RPM cruise, and high-RPM responsiveness expected from GM's flagship roadster without triggering false check engine lights.